Headphone apparatus



FIG. 1 is a front view of headphone apparatus, showing my new design;

FIG. 2 is left side view of headphone apparatus;

FIG. 3 is right side view of headphone apparatus;

FIG. 4 is bottom plan view of headphone apparatus;

FIG. 5 is top plan view of headphone apparatus; and

FIG. 6 is perspective view of headphone apparatus. 

The ornamental design for a headphone apparatus, as shown. 